In recent years, various functions for creating e-mails in mobile phones and the like have been developed. Patent Literature 1 describes a character input conversion apparatus for changing priorities of predicted conversion candidates for character inputs according to the content of an incoming mail when a return mail is created in, for example, a mobile phone thereby improving character conversion accuracy and reducing load on character input operations. The character input conversion apparatus in Patent Literature 1 includes an incoming mail analysis device and a character input conversion device. The incoming mail analysis device includes a group information storage unit in which information obtained by grouping words into semantically related groups is stored, and an incoming mail analysis unit ranking each group based on the content of an incoming mail. The character input conversion device includes a character input unit for inputting characters, a predicted conversion priority information storage unit storing priority information of character predictive conversion, an incoming mail content consideration character predictive conversion unit performing character conversion or predictive conversion of characters in accordance with the stored priority and creating a list of conversion candidates, and a character selection determination unit determining conversion characters in the candidate list.